Jeremy, what you write makes perfect sense and is an excellent distillation of what Sheldon has written on the subject. However, in my experience theory doesn't always work out under real-world conditions. FWIW, I am a large man (6'3", 215#) with big hands (size 8.5 glove) and a strong grip (take my word for it). In wet conditions with a heavy load and a steep descent I have found Neo-Retros to function more as speed modulators than proper brakes, no matter how hard I squeeze. So far I am happier with the Touring cantis, but they've only been on the bike for a month or so and it's been pretty dry during that time, so it isn't an apples-to-apples comparison. The rain is coming though, so stay tuned...
Jay Lonner Bellingham, WA On Tuesday, August 30, 2016 at 8:03:37 PM UTC-7, Jeremy Till wrote: > > It may help to clarify a few things here, and define terms. Braking > "power" is a tricky term, but for the purposes of my post we could define > it as amount of normal force applied by the brake pad to the rim. This is > dependent on the mechanical advantage of the braking system (brake, cables, > and levers), the spring tension of the brakes, and the grip strength of the > rider. For the purposes of this discussion we will ignore secondary > factors in braking such as cable stretch, housing compression, and brake > pad friction. > > Mechanical advantage (or leverage) is likewise a tricky term. It refers > specifically to how much the braking system multiplies the force applied to > the brake lever by the rider. Taken simplistically, therefore, it could be > understood as the main determinant of power, as in "v-brakes are more > powerful than cantis." However; mechanical advantage is not power for > nothing; just like a simple lever, in order to taken advantage of leverage, > we have to apply that power over a distance. The brake lever travels > farther than the brake pad over the course of the braking action. The > bigger the mechanical advantage of the system, the farther your fingers > have to travel. In the end, the power (remember, that's total braking > force) of high mechanical advantage systems can be limited by the amount of > travel the lever has between its resting point and bottoming out on the > handlebar. Since the brake pad is not moving very far, they also have the > disadvantage of requiring the brake pads to be run very close to the rim, > requiring exacting brake adjustment and wheel trueness. > > Low mechanical advantage systems, on the other hand, often are not limited > by lever travel. Since the leverage ratio is smaller, the total distance > the brake lever has to travel is smaller, well within the range of most > contemporary brake lever designs, even when adjusted for smaller reach. It > just means that the force you have to apply to the brake lever in order to > achieve a given "power" (braking force) is larger than it would be with a > higher mechanical advantage system. In other words, it comes down to grip > strength. If you have plenty of grip strength and squeeze really hard, a > low mechanical advantage system can let you achieve very high braking force > without ever reaching the limits of your brake levers. They also have the > advantage of allowing the brake pads to run farther from the rim, so aren't > as depending on exacting setup and perfectly true wheels. > . > So in the end, it comes down to the particular rider: the dimensions of > their hands, their grip strength, and their personal preferences. If you > are limited in grip strength, you would probably prefer a high mechanical > advantage system. However, given that most riders with lower grip strength > also have smaller hands and have to limit the reach of their brake levers, > this means that lever travel becomes the limiting factor in most high > mechanical advantage systems. While they multiply hand force more, they > are limited by how far the brake lever can go before hitting the bar. They > have a limit beyond which you cannot physically brake anymore, even if you > were stronger. On the the other hand, folks with big hands and a firm > handshake can run a low mechanical advantage system, run their brake levers > as far out as they'll go, and be just fine. Since the're not limited by > level travel, they harder they pull, the harder the brakes will press on > the rim. > > What does this have to do with the braking components offered by Paul? > Well, here's the rub (pun intended): I'm fairly certain that the > mid-profile Touring Canti has more mechanical advantage than the > high-profile Neo-Retro. Does that mean that they are absolutely more > powerful than the Neo-Retros? Not necessarily; they just create a system > that is limited more by lever travel than the grip strength of the rider. > I have no doubt that a rider with a strong grip could squeeze tons of > power out of a set of Neo-Retros, the type of fork-bending forces that Paul > describes in their warning. On the other hand, if you find that your > braking force "hits a wall" with Neo-Retros, that you can't pull the lever > any harder (and it is not bottoming out on the bar) and still aren't > achieving adequate stopping power, then the higher mechanical advantage > Touring Cantis might be right for you, both on the front and back. > > Paul are amazing machinists and fabricators, who care about longevity and > serviceability more than a lot of companies in the bike market. They are > not necessarily super original when it comes to design, however, especially > of their brakes. Pretty much all of their brakes are copies of other brake > designs, except executed with top notch materials and attention to detail. > Paul readily admits that the design of the Neo-Retro was copied from old > Mafac tandem cantilevers, which back in the pre-MTB days were probably some > of the most powerful brakes on the market, provided you were strong enough > to squeeze them. Tandem captains are almost by definition bigger, stronger > folks. Then along came MTBs and people of all sizes and grips strengths on > single bikes with fat tires needed more powerful brakes, and along came > lower-profile cantilever brakes, of which the Touring Canti is an excellent > example. > > On Wednesday, August 24, 2016 at 4:49:20 PM UTC-7, René wrote: >> >> Hi all, >> >> I've had Paul Cantis on my Atlantis (and Hunqapillar) since I acquired >> them. Paul Centerpulls on the Homer after using the original Silver brakes, >> and now will have Compass brazed Centerpulls on the custom. I've also read >> everything I could find, including BQ's excellent volume on brakes to >> understand how to adjust these brakes properly. >> >> The question is regarding the brakes on my Atlantis. On the front it has >> the Paul Neo-Retro and on the rear the Paul Tourer. Per my education, the >> Neo-Retro needs the cable yoke to be as high as possible and the Tourer as >> low as possible for optimal function. >> >> When braking, the rear Tourer brake which by design should be less >> powerful, feels excellent, both in braking power and modulation. In fact, I >> can brake really well with it alone, and use it primarily to slow down >> prior to turns. >> >> Braking with the front Neo-Retro feels as if it has very little power and >> is very hard to stop the bike unless you press really hard. It doesn't feel >> as if it modulates, it's just that it's hard to stop the wheel. >> >> My experience before was usually the opposite, where the rear brake >> wasn't enough on its own, but you had to be careful with the front. >> >> I changed the pads on both brakes to see if that made a difference, but >> it didn't. >> >> Is there anything I'm missing? Is that just how these brakes work? I'm >> tempted to switch the front Neo-Retros for a set of Tourer brakes that were >> in the rear of my Hunqapillar, but am concerned I won't be able to get the >> cable yoke low enough with the front rack attachment. >> >> Any feedback would be appreciated. >> >> René >> > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
